Method and apparatus for signaling user equipment status information for uplink packet transmission in a soft handover region

ABSTRACT

A method and apparatus are provided for transmitting user equipment (UE) status information in communication with one serving Node B and at least one non-serving Node B in a mobile communication system. The method and apparatus comprise generating transport channel data including UE status information; transmitting the transport channel data to the serving Node B and the at least one non-serving Node B, receiving a response signal for the transport channel data from the serving Node B, and retransmitting the transport channel data if the response signal received from the serving Node B is a non-acknowledge (NACK) signal, and ending the retransmission of the transport channel data if the response signal received from the serving Node B is an acknowledge (ACK) signal.

PRIORITY

This application is a continuation of U.S. patent application Ser. No.11/196,481, filed on Aug. 4, 2005, now pending, which in turns claimsthe benefit under 35 U.S.C. §119(a) of an application filed in theKorean Intellectual Property Office on Aug. 7, 2004 and assigned SerialNo. 2004-62265, and an application filed in the Korean IntellectualProperty Office on Nov. 11, 2004 and assigned Serial No. 2004-92154, theentire contents of both of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to asynchronous Wideband CodeDivision Multiple Access (WCDMA) communication. In particular, thepresent invention relates to a method and apparatus for signaling userequipment (UE) status information for uplink packet transmission in asoft handover region.

2. Description of the Related Art

A Universal Mobile Telecommunications Service (UMTS) system which is a3^(rd) generation mobile communication system that is based on GlobalSystem for Mobile Communications system (GSM) which is a European mobilecommunication system and uses Wideband Code Division Multiple Access(WCDMA), provides a consistent service capable of transmittingpacket-based text, digitalized audio or video, and multimedia data at ahigh rate of 2 Mbps or higher no matter where mobile phone users orcomputer users are located. UMTS uses the concept of virtual accesscalled “packet-switched access” that uses a packet protocol likeInternet Protocol (IP) to access any terminal in the network.

FIG. 1 is a diagram illustrating a configuration of a conventional UMTSTerrestrial Radio Access Network (UTRAN). Referring to FIG. 1, a UTRAN12 includes radio network controllers (RNCs) 16 a and 16 b, and Node Bs18 a, 18 b, 18 c and 18 d, and connects a user equipment (UE) 20 to acore network 10. Each of the Node Bs 18 a, 18 b, 18 c and 18 d can havea plurality of cells in its lower layer. The RNCs 16 a and 16 b eachcontrol their associated Node Bs 18 a, 18 b, 18 c and 18 d in theirlower layers. For example, in FIG. 1, the RNC 16 a controls the Node Bs18 a and 18 b, and the RNC 16 b controls the Node Bs 18 c and 18 d. TheNode Bs 18 a, 18 b, 18 c and 18 d each control their associated cells.One RNC and its associated Node Bs and cells controlled by the RNCconstitute a radio network subsystem (RNS) 14 a or 14 b.

Each of the RNCs 16 a and 16 b assigns or manages radio resources of itsNode Bs 18 a to 18 d, and each of the Node Bs 18 a to 18 d provides theradio resources. The radio resources are generated per cell, and theradio resources provided by the Node Bs 18 a to 18 d refers to radioresources of cells managed by the Node Bs themselves. The UE 20 cancreate a radio channel using a radio resource provided by a particularcell of a particular Node B, and perform communication using the createdradio channel. Because distinguishing between Node Bs 18 a to 18 d andtheir associated cells is meaningless to the UE 20 and the UE 20recognizes only the physical layers created per cell, the terms “Node Bs18 a to 18 d” and “cells” will be used herein interchangeably.

An interface between the UE 20 and RNCs 16 a and 16 b is called a Uuinterface, and its detailed hierarchical structure is illustrated inFIG. 2.

FIG. 2 is a diagram illustrating a hierarchical structure representingan interface between a UE and an RNC. The Uu interface is divided into acontrol plane 30 used for control signal exchange between the UE 20 andthe RNCs 16 a and 16 b and a user plane 32 used for actual datatransmission.

Referring to FIG. 2, the control-plane (C-plane) 30 has a radio resourcecontrol (RRC) layer 34, a radio link control (RLC) layer 40, a mediaaccess control (MAC) layer 42, and a physical (PHY) layer 44, and theuser-plane (U-plane) 32 has a packet data control protocol (PDCP) layer36, a broadcast/multicast control (BMC) layer 38, the RLC layer 40, theMAC layer 42 and the PHY layer 44. Among the layers illustrated herein,the PHY layer 44 is located in each cell and the MAC layer 42 throughthe RRC layer 34 can be located in a RNC.

The PHY layer 44 provides an information transfer service using a radiotransfer technique, and corresponds to Layer 1 (L1) of the OpeningSystems Interconnection (OSI) model. Connection between the PHY layer 44and the MAC layer 42 is achieved by transport channels, and thetransport channels are defined according to how specific data isprocessed in the PHY layer 44.

The MAC layer 42 is connected to the RLC layer 40 through logicalchannels. The MAC layer 42 delivers data received through a logicalchannel from the RLC layer 40 to the PHY layer 44 through a propertransport channel, and delivers data received through a transportchannel from the PHY layer 44 to the RLC layer 40 through a properlogical channel. In addition, the MAC layer 42 inserts additionalinformation into data received through a logical channel or a transportchannel, or analyzes additional information inserted into data andperforms an appropriate operation according to the analyzed additionalinformation. Further, the MAC layer 42 controls a random accessoperation. In the MAC layer 42, a part related to the user plane 30 iscalled MAC-d, and a part related to the control plane 32 is calledMAC-c.

The RLC layer 40 manages setup and release of a logical channel. The RLClayer 40 can operate in one of three operation modes comprising anacknowledged mode (AM), an unacknowledged mode (UM) and a transparentmode (TM), and each operation mode provides a different function.Generally, the RLC layer 40 has a function of disassembling orassembling a service data unit (SDU) provided from an upper layer in anappropriate size, and an error correction function.

The PDCP layer 36 is located in an upper layer of the RLC layer 40 inthe user plane 32, and has a function of compressing and decompressing aheader of data transmitted in the form of an IP packet and a function oflosslessly-transmitting data in a situation where a RNC providing amobile service to a particular UE is changed.

A characteristic of the transport channels connecting the PHY layer 44to its upper layers is determined by a transport format (TF) thatdefines physical layer processing processes, such as convolutionalchannel encoding, interleaving and service-specific rate matching.

A UMTS system uses an enhanced uplink dedicated channel (E-DCH) so as toenhance packet transmission performance in uplink communication from aUE to a Node B. In order to support stabilized high-speed datatransmission, the E-DCH supports such techniques as Hybrid AutomaticRetransmission Request (HARM) and Node B-controlled scheduling. In theMAC layer, a part managing processing of the E-DCH is called MAC-e.

FIG. 3 is a diagram illustrating a conventional method of transmittingdata over an E-DCH in a radio uplink. Referring to FIG. 3, referencenumeral 100 represents a Node B supporting the E-DCH, and referencenumerals 101, 102, 103 and 104 represent UEs transmitting the E-DCH. TheNode B 100 analyzes channel conditions of the UEs 101 through 104 thatuse the E-DCH, and schedules data rates of the UEs 101 through 104according to the analysis result. In order to increase the entire systemperformance, the scheduling is performed in such a manner that UEs(e.g., UEs 103 and 104) located farther from the Node B 100 is assigneda lower data rate and UEs (e.g., UEs 101 and 102) located nearer to theNode B 100 is assigned a higher data rate as long as a measuredRise-over-Thermal (RoT) value of the Node B 100 does not exceed a targetRoT value.

FIG. 4 is a signaling diagram illustrating a conventional procedure fortransmitting and receiving messages over an E-DCH. Referring to FIG. 4,in step 202, a Node B and a UE set up an E-DCH therebetween. The E-DCHsetup process 202 includes a process of transmitting messages through adedicated transport channel. After the E-DCH setup, the UE provides UEstatus information to the Node B in step 204. The UE status informationcan include UE's transmission power information representing uplinkchannel information, information on available extra power of the UE, andthe amount of transmission data piled in a UE's buffer.

In step 206, the Node B, which receives scheduling information from aplurality of UEs in communication with the Node B, monitors UE statusinformation received from the plurality of UEs in order to schedule adata rate of each UE. In step 208, the Node B determines to grant the UEto transmit an uplink packet and transmits scheduling assignmentinformation to the UE. The scheduling assignment information includes agranted maximum data rate and granted transmission timing.

In step 210, the UE determines a transport format (TF) of the E-DCH tobe transmitted in a reverse direction, using the scheduling assignmentinformation. The UE transmits uplink (UL) packet data over the E-DCH instep 212, and at the same time, transmits the TF information, i.e., atransport format resource indicator (TFRI), to the Node B in step 214.In step 216, the Node B determines whether there is an error in the TFinformation and the packet data. In step 218, the Node B transmits anon-acknowledge (NACK) to the UE over an ACK/NACK channel if there is anerror in any of them. However, if there is no error in both of them, theNode B transmits an acknowledge (ACK) to the UE through the ACK/NACKchannel.

If the ACK is transmitted indicating the completed transmission of thecorresponding packet data, the UE transmits new data through the E-DCH.However, if the NACK is transmitted indicating the transmission error ofthe corresponding packet data, the UE retransmits the same packet dataover the E-DCH.

The E-DCH, as it is an upgraded dedicated channel (DCH) for packettransmission of the transport channel, has the basic characteristics ofthe dedicated channel, and one of the characteristics is to support softhandover. When the soft handover is supported, a UE located in a softhandover region can set up E-DCHs to all of Node Bs included in itsactive set.

FIG. 5 is a diagram illustrating a conventional operation for supportingsoft handover for an E-DCH. Referring to FIG. 5, a UE 504 includes NodeBs 501, 502 and 503 in its active set. In uplink power control, the UE504 creates one combined transmit power control command (TPC) bycombining a TPC#1 506 transmitted from the Node B#1 501, a TPC#2 507transmitted from the Node B#2 502, and a TPC#3 508 transmitted from theNode B#3 503, and determines transmission power for uplink transmissionof E-DCH data 505 depending on the combined TPC. According to theconventional TPC combining method, the UE 504 decreases transmissionpower of the E-DCH 505 by a predetermined value if any one of the TPCs506, 507 and 508 is a DOWN command, and increases the transmission powerof the E-DCH 505 by a predetermined value if all of the TPCs 506, 507and 508 are UP commands. This method is called an “OR-of-DOWN method.”

The UE 504 in soft handover performs a HARQ operation in the followingmanner. The UE 504, after transmitting the E-DCH data 505, receivesACKs/NACKs 511, 512 and 513 from the Node Bs 501, 502 and 503,respectively. If any one of the ACKs/NACKs is an ACK signal, the UE 504ends the HARQ operation, i.e., a retransmission operation, on thecurrent E-DCH data 505. However, if all of the ACKs/NACKs 511, 512 and513 are NACK signals, the UE 504 retransmits the same E-DCH data 505.

That is, if only the Node B#1 501 receive the E-DCH data 505 transmittedby the UE 504 without error and the other Node Bs 502 and 503 fail tonormally receive the E-DCH data 505 transmitted by the UE 504, a RNC 510to which the Node Bs 501, 502 and 503 are connected can correctlyreceive information included in the E-DCH data 505 transmitted by the UE504. Therefore, if only one of the Node Bs 501, 502 and 503 included inthe active set succeeds in receiving the E-DCH data 505, the HARQretransmission is no longer required.

The UE located in the soft handover region simultaneously receivesscheduling assignment information related to the E-DCH from several NodeBs included in the active set. Among the Node Bs included in the activeset, a Node B having the best condition for scheduling the UE isselected as a best scheduling Node B (that is, serving Node B), and theother Node Bs are selected as non-best scheduling Node Bs (that is,non-serving Node Bs). Non-serving Node Bs refer to Node Bs that areincluded in the active set of the UE but have failed to be selected asthe serving Node B. Compared with the non-serving Node Bs, the servingNode B has a higher authority in scheduling the UE located in the softhandover region. The UE determines a transport format (data rate, codingrate, etc.) of the E-DCH to be transmitted in the uplink direction bycombining scheduling assignment information from the serving Node B withscheduling assignment information from the non-serving Node Bs.

While a scheduling method of the serving Node B is used at the sameratio as the method used for scheduling UEs located in a non-softhandover region, scheduling of the non-serving Node B is performed in apassive method for minimizing interference to other Node Bs included inthe active set. That is, compared with the scheduling assignmentinformation of the non-serving Node B, the scheduling assignmentinformation of the serving Node B becomes a greater factor indetermining an E-DCH by the UE.

However, the UE located in the soft handover region undergoes uplinktransmission power control not only by the serving Node B but also bythe non-serving Node B. Therefore, if the non-serving Node B is superiorto the serving Node B in terms of uplink channel conditions, the UE mayfollow a TPC of the non-serving Node B. Because the transmission powerof the UE is controlled based on the non-serving Node B, the UE statusinformation can be received at the serving Node B at a very high errorrate. In this case, the serving Node B can barely detect the UE statusinformation. In the conventional E-DCH technology, the serving Node B,although it has a high authority, performs scheduling using incorrect UEstatus information, deteriorating scheduling performance.

SUMMARY OF THE INVENTION

Therefore, to address the above described problem, exemplary embodimentsof the present invention provide signaling method and apparatus for userequipment (UE) status information for scheduling of enhanced uplinktransport channels for UEs located in a soft handover region in anasynchronous Wide-band Code Division Multiple Access (WCDMA)communication system.

In addition, an exemplary aspect of the present invention provides amethod and apparatus in which, when a UE located in a soft handoverregion transmits UE status information using media access control(MAC)-e signaling, a serving Node B can correctly receive the UE statusinformation.

According to one exemplary aspect of the present invention, a method isprovided for transmitting user equipment (UE) status information by a UEin communication with one serving Node B and at least one non-servingNode B in a mobile communication system supporting an uplink packet dataservice. The method comprises the steps of generating transport channeldata comprising UE status information, transmitting the transportchannel data to the serving Node B and the at least one non-serving NodeB, receiving a response signal for the transport channel data from theserving Node B, retransmitting the transport channel data if theresponse signal received from the serving Node B is a non-acknowledge(NACK) signal, and ending the retransmission of the transport channeldata if the response signal received from the serving Node B is anacknowledge (ACK) signal.

According to another exemplary aspect of the present invention, a methodis provided for transmitting user equipment (UE) status information by aUE in communication with one serving Node B and at least one non-servingNode B in a mobile communication system supporting an uplink packet dataservice. The method comprises the steps of generating transport channeldata comprising UE status information, transmitting the transportchannel data to the serving Node B and the at least one non-serving NodeB; receiving response signals for the transport channel data from theserving Node B and the at least one non-serving Node B, transmittingtransport channel data comprising the UE status information and newpacket data to the serving Node B and the at least one non-serving NodeB if the response signal received from the serving Node B is anon-acknowledge (NACK) signal and the response signal received from theat least one non-serving Node B is an acknowledge (ACK) signal, andending the transmission of the transport channel data if the responsesignal received from the serving Node B is an ACK signal.

According to further another exemplary aspect of the present invention,a user equipment (UE) apparatus is provided for transmitting UE statusinformation to one serving Node B and at least one non-serving Node B ina mobile communication system supporting an uplink packet data service.The apparatus comprises a generator for generating transport channeldata comprising UE status information, a transmitter for transmittingthe transport channel data to the serving Node B and the at least onenon-serving Node B, and a receiver for receiving a response signal forthe transport channel data from the serving Node B. The transmitterselectively retransmits the UE status information according to theresponse signal received from the serving Node B without considering aresponse signal received from the at least one non-serving Node B if thetransport channel data includes the UE status information.

According to yet another exemplary aspect of the present invention, amethod is provided for transmitting uplink packet data by a userequipment (UE) in communication with one serving Node B and at least onenon-serving Node B in a mobile communication system supporting an uplinkpacket data service. The method comprises the steps of generating firstcontrol channel data indicating a transport format of transport channeldata having packet data for the uplink packet data service and secondcontrol channel data comprising UE status information, determining firsttransmission power for the first control channel data according to powercontrol commands received from the serving Node B and the at least onenon-serving Node B, setting a predetermined power offset value for thesecond control channel data, determining second transmission power forthe second control channel data by adding the power offset value to thefirst transmission power, applying channel gains for the firsttransmission power and the second transmission power to the firstcontrol channel data and the second control channel data, andtransmitting the channel gain-applied first control channel data andsecond control channel data after multiplexing.

According to still another exemplary aspect of the present invention, auser equipment (UE) apparatus is provided for transmitting uplink packetdata to one serving Node B and at least one non-serving Node B in amobile communication system supporting an uplink packet data service.The apparatus comprises a first control channel generator for generatingfirst control channel data indicating a transport format of transportchannel data having packet data for the uplink packet data service, asecond control channel generator for generating second control channeldata comprising UE status information, and a multiplexer for multiplyingthe first control channel data by a first power gain for firsttransmission power, multiplying the second control channel data by asecond power gain for second transmission power, and transmitting thepower gain-multiplied first control channel data and second controlchannel data after multiplexing. The second transmission power isdetermined by adding a predetermined power offset for the second controlchannel data to the first transmission power.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other exemplary objects, features and advantages of thepresent invention will become more apparent from the following detaileddescription of exemplary embodiments of the present invention when takenin conjunction with the accompanying drawings in which like referencesymbols indicate the same or similar components, wherein:

FIG. 1 is a diagram illustrating a conventional configuration of a UMTSTerrestrial Radio Access Network (UTRAN);

FIG. 2 is a diagram illustrating a hierarchical structure representingan interface between a user equipment (UE) and radio network controllers(RNC);

FIG. 3 is a diagram illustrating a conventional method of transmittingdata over an E-DCH in a radio uplink;

FIG. 4 is a signaling diagram illustrating a conventional procedure fortransmitting and receiving messages over an enhanced uplink dedicatedchannel (E-DCH);

FIG. 5 is a diagram illustrating a conventional operation of supportingsoft handover for an E-DCH;

FIG. 6 is a diagram illustrating a structure of an exemplary mediaaccess control (MAC)-e packet data unit (PDU) according to an exemplaryembodiment of the present invention;

FIG. 7 is a diagram illustrating an exemplary structure of a transmitterfor transmitting MAC-e signaling E-DCH data with UE status informationaccording to an exemplary embodiment of the present invention;

FIG. 8 is a diagram illustrating an exemplary structure of a Node Breceiver for receiving MAC-e signaling E-DCH data with UE statusinformation according to an exemplary embodiment of the presentinvention;

FIG. 9 is a flowchart illustrating an exemplary implementation of anoperation of a UE according to an exemplary embodiment of the presentinvention;

FIG. 10 is a diagram illustrating an exemplary structure of a UEtransmitter according to an exemplary embodiment of the presentinvention;

FIG. 11 is a diagram illustrating an exemplary structure of a Node Breceiver according to an exemplary embodiment of the present invention;and

FIG. 12 is a flowchart illustrating an exemplary implementation of anoperation of a UE according to an exemplary embodiment of the presentinvention.

Throughout the drawings, the same or similar elements are denoted by thesame reference numerals.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Several exemplary embodiments of the present invention will now bedescribed in detail with reference to the accompanying drawings. In thefollowing description, a detailed description of known functions andconfigurations incorporated herein has been omitted for conciseness.

The exemplary embodiments of the present invention provide a signalingmethod and apparatus in which a user equipment (UE) located in a softhandover region efficiently transmit UE status information to a servingNode B. When the UE located in a soft handover region transmits UEstatus information to Node Bs included in its active set by performinguplink transmission power control using an exemplary OR-of-DOWN method,the UE status information can be correctly transmitted to the servingNode B.

The UE status information comprises, for example, at least one of bufferstatus information indicating the amount of data stored in a buffer ofthe UE, uplink transmission power information indicating uplink channelconditions of the UE, and power margin information indicating availablepower for the UE. A method for transmitting the UE status information toa Node B is divided into a physical channel signaling method in whichphysical channels are used, and a MAC-e signaling method for comprisingat least data and the UE status information in a MAC-e header or apayload of a packet data unit (PDU) generated in a MAC-e layer andtransmitting it through an enhanced uplink dedicated channel (E-DCH).

FIG. 6 is a diagram illustrating an exemplary structure of a MAC-e PDUaccording to an exemplary embodiment of the present invention. Referringto FIG. 6, at least one MAC-e service data unit (SDU) 602 represents apayload of a MAC-e PDU 603, and the MAC-e PDU 603 is created by adding aMAC-e header 601 comprising the information inserted in a MAC-e layer,to the at least one MAC-e SDU 602. The MAC-e PDU 603 is called E-DCHdata. In the MAC-e signaling process, UE status information is includedin the MAC-e header 601 or the MAC-e SDU 602.

This exemplary embodiment provides a MAC-e signaling method in which aUE located in a soft handover region accurately transmits its UE statusinformation to a serving Node B in the process of transmitting the UEstatus information to Node Bs.

The UE transmits the UE status information to Node Bs using a signalingmethod such as an exemplary MAC-e signaling method. In the MAC-esignaling method, the UE status information is included in E-DCH databefore being transmitted. If there is no transmission packet data, theE-DCH data can include only the UE status information. Because the E-DCHsupports Hybrid Automatic Retransmission Request (HARQ), the E-DCHcomprising the UE status information is also accompanied with an HARQoperation. Also, the Node Bs included in an active set of the UE locatedin a soft handover region independently perform the HARQ operation, andeach of the Node Bs checks an error in signaling information such asE-DCH data comprising UE status information (hereinafter referred to as“MAC-e signaling E-DCH data”), and sends an ACK/NACK signal according tothe error check result.

In this exemplary embodiment, in a HARQ operation for MAC-e signalingE-DCH data with UE status information, a UE uses only the ACK/NACKsignal of the serving Node B as a criterion for determining ACK/NACK.That is, even though a non-serving Node B transmits an ACK as a responseto the MAC-e signaling E-DCH data with UE status information, once theserving Node B transmits a NACK, the UE performs retransmission on theMAC-e signaling E-DCH data with UE status information. The HARQretransmission operation is performed within a predetermined maximumnumber of retransmissions (hereinafter referred to as a “maximumretransmission number”).

With reference to FIG. 7, a description will now be made of an exemplaryimplementation of an operation of performing a retransmission operationon the MAC-e signaling E-DCH data with UE status information until aserving Node B transmits an ACK signal.

FIG. 7 is a diagram illustrating an exemplary structure of a transmitterfor transmitting MAC-e signaling E-DCH data with UE status informationaccording to an exemplary embodiment of the present invention. Referringto FIG. 7, if there is a need to transmit UE status information 702,packet data 701 and the UE status information 702 are multiplexed in amultiplexer (MUX) 703, creating E-DCH data 704. If there is no packetdata 701 to transmit, the multiplexer 703 creates the E-DCH data 704with only the UE status information 702. Determining whether the UEstatus information 702 is transmitted in the current transmission timeinterval (TTI) is achieved by a UE status reporting controller 725. TheUE status reporting controller 725 controls the multiplexer 703 througha control signal 726, and multiplexes the UE status information 702 andthe packet data 701 if there is a need for transmission of the UE statusinformation 702, and otherwise, to output only the packet data 701. Ifthere is no packet data 701 as well, the E-DCH data 704 will not becreated. That is, at least one of UE status information and packet data701 is needed to create E-DCH data 704. A method in which the UE statusreporting controller 725 determines whether to transmit the UE statusinformation 702 is divided into a periodic method and an event-triggeredmethod.

The E-DCH data 704 output from the multiplexer 703 is input to a cyclicredundancy code (CRC) attachment unit 705. The CRC attachment unit 705attaches a CRC to the E-DCH data 704, and outputs the CRC-attached E-DCHdata 704 to a code block segmentation unit 706. The code blocksegmentation unit 706 segments the CRC-attached E-DCH data 704 into codeblocks appropriate in size for input information to a channel codingunit 707, and outputs the code blocks to the channel coding unit 707.The channel coding unit 707 channel-codes the code blocks, and outputsthe channel-coded information to a HARQ & rate matching unit 708. TheHARQ & rate matching unit 708 performs rate matching on thechannel-coded information, and outputs the rate-matched information toan interleaving & physical channel mapping unit 709. The interleaving &physical channel mapping unit 709 interleaves the rate-matchedinformation and maps the interleaved information into physical channeldata 730 for an enhanced dedicated physical data channel (E-DPDCH). TheE-DPDCH data 730 is multiplexed with dedicated physical data channel(DPDCH) data 712, dedicated physical control channel (DPCCH) data 711,and E-DPCCH data 713 for carrying TF-related information of the E-DCH ina multiplexer 710, and then transmitted to a Node B.

The HARQ & rate matching unit 708 determines whether to retransmit theE-DCH data 704 according to response signals received by an undepictedreceiver from a serving Node B and a non-serving Node B. In particular,MAC-e signaling E-DCH data with UE status information is retransmittedwithin the maximum amount of permitted retransmissions until the servingNode B transmits an ACK signal. In this case, it is not possible toobtain macro diversity gain due to soft handover. However, because powercontrol is performed by taking the macro diversity gain into account,there is a need for an additional method for compensating for theintentionally renounced macro diversity gain.

In a first method, the MAC-e signaling E-DCH data with UE statusinformation is greater than general E-DCH data in terms of the HARQmaximum amount of retransmissions used therefor. Herein, the generalE-DCH data refers to E-DCH data without MAC-e signaling information. Anincrease in the HARQ maximum retransmission number increasestransmission gain, compensating for the intentionally renounced macrodiversity gain.

A control signal 723 exhibits a method for controlling the HARQ maximumamount of retransmissions. A parameter controller 722 provides thecontrol signal 723 indicating the maximum retransmission number to theHARQ & rate matching unit 708 according to a control signal 728 providedfrom the UE status reporting controller 725 and a soft handover (SHO)indication signal 721. The HARQ & rate matching unit 708 increases theHARQ maximum retransmission number by a predetermined value only whentransmitting the MAC-e signaling E-DCH data with UE status informationin a soft handover state, and otherwise, uses the exiting HARQ maximumretransmission number value. The HARQ & rate matching unit 708retransmits packet data upon each receipt of a NACK, and discards thepacket data if the number of the retransmissions (hereinafter referredto as a “retransmission number”) reaches a value of the control signal723.

In an exemplary second method, the MAC-e signaling E-DCH data with UEstatus information is greater than the general E-DCH data in terms of achannel gain used therefor. An increase in the physical channel gainincreases transmission gain, compensating for the intentionallyrenounced macro diversity gain.

A control signal 724 exhibits a method for controlling the physicalchannel gain. The parameter controller 722 provides the control signal724 indicating the physical channel gain to the interleaving & physicalchannel mapping unit 709 according to the control signal 728 providedfrom the UE status reporting controller 725 and the SHO indicationsignal 721. The interleaving & physical channel mapping unit 709increases the channel gain of the E-DPDCH data 730 by a predeterminedvalue only when transmitting the MAC-e signaling E-DCH data with UEstatus information in a soft handover state, and otherwise, uses theexiting change gain value.

A description has been made of the two exemplary methods of compensatingfor the intentionally renounced macro diversity gain for the MAC-esignaling E-DCH data with UE status information. Although the twoexemplary methods can be individually used, it is shown in FIG. 7 thatthey are used together. As an increment of the maximum retransmissionnumber and an increment of the channel gain, predetermined values areused or the values determined by analyzing conditions of Node Bs by aNode B or an RNC and then reported to a UE and a serving Node B areused.

The UE status reporting controller 725 determines whether to transmitthe UE status information 702 using the periodic method or theevent-triggered method. When the UE status information is transmitted onan event-triggered basis, a Node B receiver may have difficulty indetermining whether the received E-DCH data is MAC-e signaling E-DCHdata with UE status information or general E-DCH data without signalinginformation. Therefore, when the MAC-e signaling E-DCH data with the UEstatus information 702 is transmitted, the UE status reportingcontroller 725 comprises indication information indicating MAC-esignaling E-DCH data in the E-DPCCH data 713 specifying a transportformat (TF) of the E-DCH data, and reports the Node B that the MAC-esignaling E-DCH data is transmitted on an event-triggered basis. The UEstatus reporting controller 725 allows, through a control signal 727,the E-DPCCH data 713 to comprise a TF indicating the presence/absence ofMAC-e signaling E-DCH data or comprise a UE status informationindicator. By receiving the E-DPCCH data 713, the Node B receiver cancorrectly determine a type of the E-DCH data, i.e., determine whetherthe E-DCH data is MAC-e signaling E-DCH data.

FIG. 8 is a diagram illustrating an exemplary structure of a Node Breceiver for receiving MAC-e signaling E-DCH data with UE statusinformation according to an exemplary embodiment of the presentinvention. Referring to FIG. 8, a signal 801 received from a UE isapplied to a demultiplexer (DEMUX) 802. The demultiplexer 802demultiplexes the received signal 801 into E-DPCCH data 812, DPCCH data813, DPDCH data 814, and E-DPDCH data 830 with E-DCH data. The Node Bshould first determine whether the E-DCH data is MAC-e signaling E-DCHdata with UE status information or not. If the UE status information istransmitted on a periodic basis, a UE status reporting controller 820can detect the transmission of the UE status information by calculatingthe current period. However, if the UE status information is transmittedon an event-triggered basis, the UE status reporting controller 820 candetect the transmission of the UE status information through a TF or aUE status information indicator 821 included in the E-DPCCH data 812.The UE status information indicator 821 is input to the UE statusreporting controller 820, and the UE status reporting controller 820uses the UE status information indicator 821 to indicate whether theE-DCH data is MAC-e signaling E-DCH data with UE status information.

If it is determined that the received E-DCH data is MAC-e signalingE-DCH data with UE status information, the UE status reportingcontroller 820 controls a demultiplexer 809 using a control signal 823so as to demultiplex the E-DCH data into UE status information 810 andpacket data 811. Otherwise, the UE status reporting controller 820controls the demultiplexer 809 using the control signal 823 so as tooutput only the packet data 811.

Because the MAC-e signaling E-DCH data with UE status information isdifferent from the general E-DCH data in either one or both of the HARQmaximum retransmission number and the E-DPDCH channel gain, the receivershould also support them. The UE status reporting controller 820informs, using a control signal 822, a parameter controller 825 whetherthe received E-DCH data is MAC-e signaling E-DCH data with UE statusinformation. The parameter controller 825 creates control signals 826and 827 according to the control signal 822 and an SHO indication signal824. The control signal 826 is input to an HARQ & rate dematching unit804, and the HARQ & rate dematching unit 804 designates HARQ maximumretransmission number according to the control signal 826. The controlsignal 827 is input to a deinterleaving & physical channel demappingunit 803, and the deinterleaving & physical channel demapping unit 803controls a channel gain of the E-DPDCH data 830 according to the controlsignal 827.

The E-DPDCH data 830 is input to the deinterleaving & physical channeldemapping unit 803, and the deinterleaving & physical channel demappingunit 803 performs physical channel demapping and deinterleaving on theE-DPDCH data 830, and outputs the resultant information to the HARQ &rate dematching unit 804. The HARQ & rate dematching unit 804 performsHARQ processing and rate dematching on the input information, andoutputs the resultant information to a channel decoding unit 805. TheHARQ & rate dematching unit 804 bypasses the deinterleaved data orcombines the deinterleaved data with previously received data accordingto whether the deinterleaved data is retransmitted data, and thereafter,rate-dematches the data. The channel decoding unit 805 channel-decodesthe information rate-dematched by the HARQ & rate dematching unit 804,and outputs the channel-decoded information to a code blockconcatenation unit 806. The code block concatenation unit 806concatenates the channel-decoded information, and outputs theconcatenated information to a CRC check unit 807. The CRC check unit 807performs a CRC check on the concatenated information, and outputs theCRC-checked information as E-DCH data 808. The E-DCH data 808 isdemultiplexed into the UE status information 810 and the packet data 811by the demultiplexer 809.

If the MAC-e signaling E-DCH data with UE status information is notperiodically transmitted, i.e., if there is a need to transmit the UEstatus information on an event-triggered basis, the E-DPCCH data 812comprises a UE status information indicator indicating whether the MAC-esignaling E-DCH data is transmitted. Each of Node Bs can determinewhether it is a serving Node B or a non-serving Node B through a softhandover process and a best/non-serving Node B setting process, anddetects presence/absence of MAC-e signaling E-DCH data through the UEstatus information indicator indicating transmission/non-transmission ofthe MAC-e signaling E-DCH data.

In the process of transmitting the MAC-e signaling E-DCH data with UEstatus information, the UE located in a soft handover region determinesonly the ACK/NACK signal from the serving Node B as an effective ACKNACKsignal, and disregards the ACKNACK signal from the non-serving Node B.Therefore, the non-serving Node B is not required to transmit theACK/NACK signal when the MAC-e signaling E-DCH data with only UE statusinformation is received from the UE located in a soft handover region.Accordingly, the non-serving Node B can save downlink transmission powerby the transmission power needed for transmission of the ACK/NACKsignal.

As described above, the maximum retransmission number or the maximumamount of retransmissions set for transmission of the MAC-e signalingE-DCH data can be equal to or greater than the maximum retransmissionnumber set for transmission of the general E-DCH data. In some cases,however, the MAC-e signaling E-DCH data cannot be successfully receivedat the serving Node B within the reset maximum retransmission number. Inthis case, the UE re-includes the UE status information in the nextE-DCH data during transmission of the next E-DCH data. That is, if anACK signal for the MAC-e signaling E-DCH data is not received from theserving Node B until the current retransmission number reaches the resetmaximum retransmission number, the UE ends the retransmission of thepacket data, and transmits MAC-e signaling E-DCH data comprising a newpacket data and the UE status information in the next TTI. Aftertransmitting the next MAC-e signaling E-DCH data, the UE similarlyconsiders only the ACK/NACK signal from the serving Node B.

FIG. 9 is a flowchart illustrating an exemplary implementation of anoperation of a UE according to an exemplary embodiment of the presentinvention. Referring to FIG. 9, a UE creates transport channel data,especially, E-DCH data, in step 902, and transmits the E-DCH data aftermultiplexing it with other transport channel data in step 904. The E-DCHdata created in step 902 can comprise UE status information on aperiodic basis or on an event-triggered basis. In step 906, the UEdetermines if the E-DCH data comprises UE status information. If theE-DCH data is the general E-DCH data without UE status information, theUE determines in step 908 whether an ACK signal is received from any oneof Node Bs in response to the E-DCH data. If an ACK signal is receivedfrom any one of a serving Node B and a non-serving Node B, the UEreturns to step 902 to transmit new E-DCH data.

However, if NACK signals are received from all of the Node Bs, the UEdetermines in step 910 whether a retransmission number of the E-DCH datahas reached a first maximum retransmission number. If the retransmissionnumber of the E-DCH data has not reached the first maximumretransmission number, the UE returns to step 904 to retransmit theE-DCH data. However, if the retransmission number has reached the firstmaximum retransmission number, the UE returns to step 902 to transmitnew E-DCH data, abandoning transmission of the E-DCH data.

However, if it is determined in step 906 that the E-DCH data is MAC-esignaling E-DCH data with UE status information, the UE determines instep 912 whether an ACK signal is received from the serving Node Bwithout considering a response signal from the non-serving Node B. If anACK signal is received from the serving Node B, the UE returns to step902 to transmit new E-DCH data.

However, if a NACK signal is received from the serving Node B, the UEdetermines in step 914 whether a retransmission number of the MAC-esignaling E-DCH data has reached a second maximum retransmission numberwhich is set greater than the first maximum retransmission number. Ifthe retransmission number of the MAC-e signaling E-DCH data has notreached the second maximum retransmission number, the UE returns to step904 to retransmit the MAC-e signaling E-DCH data. However, if theretransmission number of the MAC-e signaling E-DCH data has reached thesecond maximum retransmission number, the UE returns to step 902 totransmit new E-DCH data, abandoning transmission of the E-DCH data.

Another exemplary embodiment of the present invention provides a methodfor signaling UE status information through a physical control channelby a UE located in a soft handover region. The UE can use 2E-DCH-related dedicated physical channels, i.e., an E-DPCCH1 and anE-DPCCH2. The E-DPCCH1 specifies a TF of E-DCH data being transmitted,and the E-DPCCH2 carries the UE status information independently of theE-DCH data.

A description will now be made of data transmission using the E-DPCCH1and the E-DPCCH2. Both of the information specifying a TF of E-DCH dataand the UE status information can be transmitted through an E-DPDCH oran E-DPCCH. Therefore, an exemplary embodiment of the present inventioncan be applied to all of the cases where UE status information issignaled through a physical channel.

In the case where power control is performed in a soft handover regionby combining transmit power control commands (TPCs) received fromseveral Node Bs using an OR-of-DOWN method, transmission power of theE-DPCCH1 or the E-DPCCH2 can be insufficient, so that the serving Node Bmay not correctly receive the UE status information. Therefore, thisexemplary embodiment provides a method of compensating for the lack ofthe transmission power of the E-DPCCH2.

A UE located in a soft handover region transmits the E-DPCCH2 usingtransmission power determined by adding a power offset value totransmission power of the E-DPCCH1 in a known power control method. Thatis, the transmission power of the E-DPCCH2 is higher than thetransmission power of the E-DPCCH1 by the power offset value.

Upon entering the soft handover region, the UE determines transmissionpower for the E-DPCCH2 by adding the power control offset value to thetransmission power of the E-DPCH1. As the power offset value, apredetermined value is used or the value determined by a Node B or anRNC and then reported to the UE and the Node B is used.

Alternatively, a power offset value adaptively determined within apredetermined range can be used. That is, the UE defines a limit of apower offset value, and determines the power offset value within thelimit using a difference between a TPC provided from a serving Node Band a combined TPC determined by the OR-of-DOWN method. If there is adifference between the TPC from the serving Node B and the combined TPC,the UE increases the power offset value of the E-DPCCH2 from the valueused in the previous slot by, for example, 2 dB, and if there is nodifference therebetween, the UE uses the intact power offset value usedin the previous slot.

If the TPC from the serving Node B is an UP command and the combined TPCis a DOWN command, the UE increases the power offset value. Similarly,the power offset value cannot exceed a predetermined limit. If the poweroffset value reaches the limit, the UE maintains the power offset valueat the limit even though the TPC from the serving Node B is an UPcommand and the combined TPC is a DOWN command. At this time, if the TPCfrom the serving Node B becomes a DOWN command, the power offset valueis initialized to 0 dB.

FIG. 10 is a diagram illustrating an exemplary structure of a UEtransmitter according to an exemplary embodiment of the presentinvention. Referring to FIG. 10, UE status information 1005 is comprisedof E-DPCCH2 data 1010. E-DPCCH1 data 1015 specifying a TF of E-DCH datais created by a multiplexer 1009 by multiplexing a transport formatresource indicator (TFRI) 1006 indicating a transport block format ofthe E-DCH data, HARQ-related information 1007 indicating whether toretransmit the E-DCH data, and the other information 1008. The E-DPCCH1data 1015 and the E-DPCCH2 data 1010, together with DPDCH data 1013,DPCCH data 1012, HS-DPCCH (DPCCH for high speed data packet access(HSDPA)) data 1011, and E-DPDCH data 1014 comprising E-DCH data, aremultiplied by corresponding channel gains, and then time-multiplexed orcode-multiplexed in a MUX & channel gain setting block 1016. The MUX &channel gain setting block 1016 time-multiplexes only the E-DPCCH1 data1015 and the E-DPCCH2 data 1010, and code-multiplexes the other channeldata 1011 through 1014. A channel gain of the E-DPCCH2 data 1010 isdetermined by adding a predetermined power offset value to a channelgain of the E-DPCCH1 data 1015. The multiplexed data is transmitted on atransmission signal 1017.

The MUX & channel gain setting block 1016 is controlled according to acontrol signal 1002 that is generated by a SHO controller 1001 dependingon a SHO indication signal 1000. If the SHO indication signal 1000indicates a SHO region, the SHO controller 1001 sets a power offsetvalue of the E-DPCCH2 data 1010 in the MUX & channel gain setting block1016 using the control signal 1002. The power offset value, as describedabove, can be a predetermined value, a value given by a Node B, or anadaptively variable value.

FIG. 11 is a diagram illustrating an exemplary structure of a Node Breceiver according to an exemplary embodiment of the present invention.

Referring to FIG. 11, a Node B receiver demultiplexes a signal 1117received from a UE into a variety of channel data at a demultiplexer1116. The demultiplexer 1116 outputs HS-DPCCH data 1111, DPCCH data1112, DPDCH data 1113, E-DPDCH data 1114 with E-DCH data, E-DPCCH1 data1115, and E-DPCCH2 data 1110. In the process of receiving the E-DPCCH2data 1110, the transmission power offset value set in the UE transmitterof FIG. 10 is required by the demultiplexer 1116 for interferencecancellation and reception power measurement. Because the E-DPCCH2 data1110 is received only in the soft handover region, a SHO controller 1101detects a soft handover state of the UE using the SHO indication signal1100, and informs the demultiplexer 1116 of the soft handover stateusing a control signal 1102. If the control signal 1102 indicates thesoft handover state, the demultiplexer 1116 performs demultiplexing onthe E-DPCCH2 data 1110 using the power offset value. The power offsetvalue can be a predetermined value, or a value determined by a Node B oran RNC.

A demultiplexer 1109 demultiplexes the E-DPCCH1 data 1115 to extract aTFRI 1106, HARQ-related information 1107, and the other information1108. The Node B receiver detects UE status information 1105 byreceiving the E-DPCCH2 data 1110, and schedules a data rate of the UEaccording to the UE status information 1105.

In another exemplary embodiment, a UE located in a soft handover regiontransmits UE status information with physical channel signaling using anE-DPCCH2, wherein E-DPCCH2 data comprising the UE status information isrepeatedly transmitted. In this exemplary embodiment, the UE can use twodedicated physical channels of an E-DPCCH1 and an E-DPCCH2. The E-DPCCH1specifies a TF of the E-DCH data being transmitted, and the E-DPCCH2carries the UE status information independently of the E-DCH data.

A description will now be made of data transmission using the E-DPCCH1and the E-DPCCH2. Both of the information specifying a TF of E-DCH dataand the UE status information can be transmitted through an E-DPDCH oran E-DPCCH. Therefore, this exemplary embodiment of the presentinvention can be applied to all of the cases where E-DCH data with UEstatus information is signaled through a physical channel.

In the case where power control is performed in a soft handover regionby combining TPCs received from several Node Bs using the OR-of-DOWNmethod, transmission power of the E-DPCCH1 or the E-DPCCH2 can beinsufficient, so that the serving Node B may not correctly receive theUE status information. Therefore, this exemplary embodiment compensatesfor the lack of the transmission power of the E-DPCCH2 throughretransmission.

To compensate for the lack of the transmission power of the E-DPCCH2,the UE repeatedly transmits E-DPCCH2 data two or more times uponentering a soft handover region, thereby obtaining time diversity gain.For a value of the number of repetitions (hereinafter referred to as a“repetition number”) for the E-DPCCH2, a predetermined value is used orthe value determined by a Node B or a RNC and then reported to the UEand the Node B is used.

An exemplary structure of a UE transmitter according to this exemplaryembodiment will be now described with reference to FIG. 10. Referring toFIG. 10, UE status information 1005 is comprised of E-DPCCH2 data 1010.E-DPCCH1 data 1015 specifying a TF of E-DCH data is created by amultiplexer 1009 by multiplexing a TFRI 1006 indicating a transportblock format of the E-DCH data, HARQ-related information 1007 indicatingwhether to retransmit the E-DCH data, and the other information 1008.The E-DPCCH1 data 1015 and the E-DPCCH2 data 1010, together with DPDCHdata 1013, DPCCH data 1012, HS-DPCCH data 1011, and E-DPDCH data 1014comprising E-DCH data, are multiplied by corresponding channel gains,and then time-multiplexed or code-multiplexed in a MUX & channel gainsetting block 1016.

The MUX & channel gain setting block 1016 is controlled according to acontrol signal 1002 that is generated by an SHO controller 1001depending on an SHO indication signal 1000. If the SHO indication signal1000 indicates a SHO region, the SHO controller 1001 controls arepetition number for the E-DPCCH2 data 1010 in the MUX & channel gainsetting block 1016 using the control signal 1002. Then the MUX & channelgain setting block 1016 repeatedly transmits the E-DPCCH2 data 1010 bytime multiplexing. As described above, for a value of the repetitionnumber for the E-DPCCH2, a predetermined value is used or a value givenby a Node B is used.

An exemplary structure of a Node B receiver according to this exemplaryembodiment of the present invention will now be described with referenceto FIG. 11. Referring to FIG. 11, a Node B receiver demultiplexes asignal 1117 received from a UE into a variety of channel data at ademultiplexer 1116. The demultiplexer 1116 outputs HS-DPCCH data 1111,DPCCH data 1112, DPDCH data 1113, E-DPDCH data 1114 with E-DCH data,E-DPCCH1 data 1115, and E-DPCCH2 data 1110. The E-DPCCH2 data 1110 canbe repeatedly transmitted from a UE transmitter, and the repeatedtransmission is performed only when the UE is located in a soft handoverregion. Therefore, a SHO controller 1101 controls a demultiplexer 1116using a control signal 1102 that is generated depending on a SHOindication signal 1100.

If the control signal 1102 indicates the soft handover region, thedemultiplexer 1116 combines the repeatedly received E-DPCCH2 data 1110using, for example, a maximum ratio combing method. As a value of therepetition number for the E-DPCCH2, a predetermined value is used or thevalue determined by a Node B or an RNC is used. The UE transmitter andthe Node B receiver share the same repetition number value.

Another exemplary embodiment provides a method in which a UE located ina soft handover region accurately transmits UE status information to aserving Node B in the process of transmitting the UE status informationto a Node B with a MAC-e signaling method.

The UE transmits its UE status information to Node Bs with the MAC-esignaling method. In the MAC-e signaling method, the UE statusinformation is included in E-DCH data together with packet data beforebeing transmitted. Because the E-DCH is a channel supporting HARQ, theUE status information transmitted through the E-DCH also accompanies anHARQ operation. Also, a UE located in the soft handover region and NodeBs included in an active set of the UE perform the HARQ operation, andeach of the Node Bs checks an error in E-DCH data, especially, MAC-esignaling E-DCH data, and sends an ACK/NACK signal according to theerror check result.

If any one of the ACK/NACK signals received from the Node Bs is an ACKsignal, the UE no longer performs retransmission on the MAC-e signalingE-DCH data corresponding to the ACK signal. Here, if the ACK signal wasreceived from a non-serving Node B and a serving Node B transmitted aNACK signal, the serving Node B cannot detect UE status informationincluded in the MAC-e signaling E-DCH data. Therefore, in this exemplaryembodiment, the UE repeatedly transmits the UE status information untilthe serving Node B receives the UE status information. A detailedprocess thereof will be described herein below.

The UE transmits UE status information through MAC-e signaling E-DCHdata. If a HARQ operation of the MAC-e signaling E-DCH data is ended asa serving Node B transmits a NACK signal in response to the MAC-esignaling E-DCH data and a non-serving Node B transmits an ACK signal,the serving Node B fails to receive the UE status information.

In a normal case, UE status information is generated on a periodic basisor an event-triggered basis and then transmitted on E-DCH data with theMAC-e signaling method only for a corresponding period. However, if theHARQ process ends before the serving Node B receives the UE statusinformation as described above, the UE retransmits the next packet dataand the UE status information using the MAC-e signaling method even inthe process of transmitting E-DCH data in the next period. Theretransmitted UE status information can be one of the previouslytransmitted UE status information and newly measured UE statusinformation. Even though the UE has transmitted the UE statusinformation using the MAC-e signaling method, if the HARQ process isended not in response to an ACK signal from the serving Node B, the UErepeatedly transmits the UE status information by MAC-e signaling everyTTI.

In this manner, the UE continuously transmits the UE status informationby MAC-e signaling, and stops transmission of the UE status informationat the time when the serving Node B transmits an ACK signal. That is,the moment that the serving Node B transmits an ACK signal, the UE canperceive that the serving Node B has received the UE status information.Then there is no need to retransmit the UE status information, and theUE transmits E-DCH data comprising the packet data without the UE statusinformation until the next time when UE status information should betransmitted on a periodic basis or on an event-triggered basis.

In this exemplary embodiment, the HARQ operation of the UE is constantregardless of the MAC-e signaling method for transmitting the UE statusinformation, and only the operation of creating a MAC-e PDU in a MAC-elayer is changed.

FIG. 12 is a flowchart illustrating an exemplary implementation of anoperation of a UE according to an exemplary embodiment of the presentinvention. Referring to FIG. 12, a UE creates transport channel data,especially, E-DCH data, in step 1202, and transmits the E-DCH data aftermultiplexing it with other transport channel data in step 1204. TheE-DCH data created in step 1202 can comprise UE status information on aperiodic basis or on an event-triggered basis. In step 1206, the UEdetermines if the E-DCH data comprises UE status information. If theE-DCH data is the general E-DCH data without UE status information, theUE determines in step 1208 whether an ACK signal is received from anyone of Node Bs in response to the E-DCH data. If an ACK signal isreceived from any one of a serving Node B and a non-serving Node B, theUE returns to step 1202 to transmit new E-DCH data.

However, if NACK signals are received from all of the Node Bs, the UEdetermines in step 1210 whether a retransmission number of the E-DCHdata has reached a predetermined maximum retransmission number. If theretransmission number of the E-DCH data has not reached the maximumretransmission number, the UE returns to step 1204 to retransmit theE-DCH data. However, if the retransmission number has reached themaximum retransmission number, the UE returns to step 1202 to transmitnew E-DCH data, abandoning transmission of the E-DCH data.

However, if it is determined in step 1206 that the E-DCH data is MAC-esignaling E-DCH data comprising both the UE status information and thepacket data, the UE determines in step 1212 whether an ACK signal isreceived from the serving Node B. If an ACK signal is received from theserving Node B, the UE returns to step 1202 to transmit new E-DCH data.

However, if a NACK signal is received from the serving Node B, the UEdetermines in step 1214 whether an ACK signal is received from any oneof non-serving Node Bs. If an ACK signal is received from anynon-serving Node B, the UE creates new E-DCH data comprising new packetdata and UE status information in step 1218, determining that the packetdata included in the MAC-e signaling E-DCH data will be transmitted tothe RNC through the non-serving Node B, and then returns to step 1204 totransmit the new E-DCH data.

However, if it is determined in step 1214 that NACK signals are receivedfrom all of the Node Bs, the UE determines in step 1216 whether aretransmission number of the MAC-e signaling E-DCH data has reached themaximum retransmission number. If the retransmission number of the MAC-esignaling E-DCH data has not reached the maximum retransmission number,the UE returns to step 1204 to retransmit the full MAC-e signaling E-DCHdata. However, if the retransmission number of the MAC-e signaling E-DCHdata has reached the maximum retransmission number, the UE proceeds tostep 1218 to transmit new E-DCH data, abandoning transmission of thepacket data included in the MAC-e signaling E-DCH data.

As can be understood from the foregoing description, the novel methodcan efficiently schedule a UE located in a soft handover region in theprocess of performing scheduling for uplink packet transmission in aWCDMA communication system. The UE located in a soft handover regioncorrectly and reliably reports its UE status information to a servingNode B having higher scheduling authority, thereby contributing to anincrease in scheduling performance and the entire system stability.

While the invention has been shown and described with reference tocertain exemplary embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

1. A signaling method for transmitting scheduling information forscheduling by a user equipment, UE in communication with a serving NodeB and at least one non-serving Node B in a mobile communication systemsupporting an uplink packet data service, wherein the schedulinginformation for scheduling is contained in a MAC-e packet data unit,PDU, the method comprising the steps of: generating the MAC-e PDUcontaining the scheduling information for scheduling; transmitting theMAC-e PDU to the serving Node B and the at least one non-serving Node B;and performing an Hybrid Automatic Retransmission Request, HARQ,operation for retransmitting the MAC-e PDU containing the schedulinginformation until an acknowledge, ACK, signal for the MAC-e PDU isreceived from the serving Node B with regardless of receiving an ACKsignal from the at least one non-serving Node B, wherein the schedulinginformation for scheduling is transmitted without transmission packetdata.
 2. The signaling method of claim 1, wherein the schedulinginformation is inserted in a payload of the MAC-e PDU.
 3. The signalingmethod of claim 1, further comprising the step of: performing the HARQoperation within a predetermined maximum number of retransmissions.
 4. Asignaling method for transmitting scheduling information for schedulingby a user equipment, UE in communication with a serving Node B and atleast one non-serving Node B in a mobile communication system supportingan uplink packet data service, wherein the scheduling information forscheduling is contained in a MAC-e packet data unit, PDU, the methodcomprising the steps of: generating the MAC-e PDU containing thescheduling information for scheduling; transmitting the MAC-e PDU to theserving Node B and the at least one non-serving Node B; performing anHybrid Automatic Retransmission Request, HARQ, operation forretransmitting the MAC-e PDU containing the scheduling information forscheduling until an acknowledge, ACK, signal for the MAC-e PDU isreceived from the serving Node B or the at least one non-serving Node B,wherein the scheduling information for scheduling is transmittedtogether with transmission packet data; and transmitting the schedulinginformation and a new transmission packet data in the next period if anACK signal is received from any one of non-serving Node Bs.
 5. Thesignaling method of claim 4, wherein the scheduling information isinserted in a payload of the MAC-e PDU.
 6. The signaling method of claim4, further comprising the step of: performing the HARQ operation withina predetermined maximum number of retransmissions.
 7. A user equipment,UE, apparatus for scheduling by a UE in communication with a servingNode B and at least one non-serving Node B in a mobile communicationsystem supporting an uplink packet data service, wherein the schedulinginformation for scheduling is contained in a MAC-e packet data unit,PDU, the apparatus comprising: means for generating the MAC-e PDUcontaining the scheduling information for scheduling; means fortransmitting the MAC-e PDU to the serving Node B and the at least onenon-serving Node B; means for receiving a response signal for the MAC-ePDU from to the serving Node B and the at least one non-serving Node B;and means for controlling performing an Hybrid Automatic RetransmissionRequest, HARQ, operation for retransmitting the MAC-e PDU containing thescheduling information until an acknowledge, ACK, signal in response tothe MAC-e PDU is received from the serving Node B with regardless ofreceiving an ACK signal from the at least one non-serving Node B,wherein the scheduling information for scheduling is transmitted withouttransmission packet data.
 8. The UE apparatus of claim 7, wherein themeans for generating the MAC-e PDU is further configured to insert thescheduling information in a payload of the MAC-e PDU.
 9. The UEapparatus of claim 7, wherein the HARQ operation is performed within apredetermined maximum number of retransmissions.
 10. A user equipment,UE, apparatus for scheduling by a UE in communication with a servingNode B and at least one non-serving Node B in a mobile communicationsystem supporting an uplink packet data service, wherein the schedulinginformation for scheduling is contained in a MAC-e packet data unit,PDU, the apparatus comprising: means for generating the MAC-e PDUcontaining the scheduling information for scheduling; means fortransmitting the MAC-e PDU to the serving Node B and the at least onenon-serving Node B; means for receiving a response signal for the MAC-ePDU from to the serving Node B and the at least one non-serving Node B;and means for controlling performing an Hybrid Automatic RetransmissionRequest, HARQ, operation for retransmitting the MAC-e PDU containing thescheduling information for scheduling until an acknowledge, ACK, signalfor the MAC-e PDU is received from the serving Node B or the at leastone non-serving Node B, wherein the scheduling information forscheduling is transmitted together with transmission packet data, andcontrolling the means for transmitting the MAC-e PDU and the means forgenerating the MAC-e PDU in order to transmit the scheduling informationand a new transmission packet data in the next period if an ACK signalis received from any one of non-serving Node Bs.
 11. The UE apparatus ofclaim 10, wherein the means for generating the MAC-e PDU is furtherconfigured to insert the scheduling information in a payload of theMAC-e PDU.
 12. The UE apparatus of claim 10, wherein the HARQ operationis performed within a predetermined maximum number of retransmissions.13. A signaling method of claim 1, wherein the scheduling informationcomprises at least one of buffer status information, uplink transmissionpower information and information indicating available power.
 14. Asignaling method of claim 4, wherein the scheduling informationcomprises at least one of buffer status information, uplink transmissionpower information and information indicating available power.
 15. A userequipment (UE) apparatus of claim 7, wherein the scheduling informationcomprises at least one of buffer status information, uplink transmissionpower information and information indicating available power.
 16. A userequipment (UE) apparatus of claim 10, wherein the scheduling informationcomprises at least one of buffer status information, uplink transmissionpower information and information indicating available power.